HISTORY IN BRIEF. 19 



UNITED STATES. 



Most of the experimental work on the disease has been performed 

 in the United States. References in Hterature begin about the year 

 1892, but undoubtedly the disease has been present for a long time. 

 The literature is so well known and so easily accessible that it is not 

 necessary to abstract it at any length. The most recent papers are 

 by Dr. George G. Hedgcock, of the Bureau of Plant Industry (Bulletins 

 183 and 186), and he has given therein a rather full bibhography. 



The infectious nature of the peach gall was rendered certain several 

 years ago by a number of experiment station workers who obtained 

 the growths on young trees either by planting them in the vicinity 

 of diseased ones, by mincing the galls and distributing the fragments 

 in the sand or earth near sound trees, or by grafting. Thus Thaxter 

 in Connecticut (1891 or prior), Halsted in New Jersey (1897), Selby in 

 Ohio (1898). Toumey in Arizona (1900) proved in the same ways 

 the infectious nature of the almond gall. 



As the result of his experiments on almonds Toumey concluded the 

 disease to be due to a slime mold described by him as DendropJiagus 

 glohosus, but this statement is not sufficiently supported by infection 

 experiments and is regarded by the writers as wholly erroneous. 

 Toumey made only a few inoculations and none with indubitably 

 pure material, i. e., his inoculating material oozed from the cut sur- 

 face of galls which undoubtedly contained the bacteria here described. 

 It was never grown in pure cultures. Of liis 10 inoculations 3 only 

 yielded galls. 



Hedgcock subsequently cross-grafted fragments of galls success- 

 fully on some fruit trees and unsuccessfully on others. His general 

 conclusions, however, have differed so materially in his various papers 

 tliat the reader is referred to his texts. 



Under the name of necrosis of the grapevine (Cornell Univ. Bull, 

 No. 263, Feb., 1909), Reddick figured this disease and ascribed it to 

 Fusicoccum viticolum n. sp., but on insufficient evidence, as he has 

 since admitted (2d Meeting Am. Phytopath. Soc). 



This disease, which is commonly known as crown-gall, occurs, on 

 one plant or another, in all parts of the United States. Toumey's 

 inquiries in 1900 showed it present in 22 States, to which all the others 

 may now be added. 



SOUTH AMERICA. 



In Chile, according to Delacroix, this disease as it occurs on the 

 vine has been ascribed by Lataste to the root coccid, Margarodes 

 vitium."- 



Solano has reported the disease as occurring on the grapevine in 

 Peru (1910). 



o Possibly two diseases are confused. The woolly aphis (Schizoneura) induces small galls on stems and 

 roots of the apple and those on the roots have been confused with crown galls. 

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